Adjustable piano-string plate.



F. J. W. WEISER. ADJUSTABLE PIANO STRING PLATE. APPLIOATION FILED AUG.28, 1911.-

1,097,694. Pat nted May 26, 1914.

E X) 59 Z 5 Q n J; i Z Z a z E 2 V I e UNITED STATES PATENT OFFICE.

FRANK J. W. wnrsnn, or cnrcsco, ILLINOIS, ASSIGNOR T0 cnoaen r. BENT COMPANY, or CHICAGO, rumors, A CORPORATION or ILLINOIS.

ADJUSTABLE PIANO-STRING PLATE.

To all whom it may concern Be it known that I, F RANK J. WV. \Vmsnn, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Adjustable Piano-String Plates, of which the following is a specification, reference being had therein to the ac companying drawing.

My invention provides means to regulate the pressure or hearing of piano strings on the sounding-board bridge, and consists in the matters hereinafter described, and pointed out in the appended claims.

After pianos have been used there is a tendency for the sounding-board to settle or pull back from the strings, so that there is less pressure of the strings on the bridge than when the instrument was first made; in others words, the original arching of the board is not maintained, with the result that the tone is not so strong. Also it frequently occurs that the sounding-board will buckle up from dampness and destroy its original arching. By adjustably mounting the lower end of the string-plate at a spaced distance from the soundingboard this end of the plate may be adjusted toward or away from the sounding-board to restore the original pressure of the strings on the bridge, so that the effect of the original pressure is restored and proper pressure of the strings on the bridge is maintained.

The object of my invention is to provide a practical and readily operated means for restoring this pressure which may be utilized without returning the piano to the factory.

In the accompanying drawings which illustrate an embodiment of my invention Figure l is a vertical sectional view of a piano back-frame, sounding-board, and adjustable plate on which the strings are strung showing a practical means of Carrying out my invention, and Fig. 2 is a transverse sectional view on the line 22 of Fig. 1.

In the drawings A represents the back frame consisting of top and bottom pieces a, a, and connecting uprights a with filler pieces a at their lower ends, B the sounding board secured to the back-frame and having the usual wooden bridges Z), the pin-blook b at its upper end, and the usual acoustic rim or lining 6 The reference letter C represents the metal plate to which the vibrating strings 0 are Specification of Letters Patent.

Application filed August 28, 1911.

Patented May 26, 1914.

Serial No. 646,458.

strung in the usual manner and overlying the sounding-board bridges, the upper end of the plate overlying the usual wrest plank on the pin-block by which it is spaced away from the board. The string plate G is of the usual form and contour having the ribs or bars 0 and is secured to the back frame at its top by screws or bolts D and at its bot-- tom by any form of attaching device which will permit the plate to be adjusted with relation to the back to regulate the pressure of the strings upon the bridge; in the drawings I show a practical means for this purpose consisting of a plurality of adjusting bolts or screws E passing freely through the lower end of the plate C and adjustably engaging the back-frame by their screw threads and provided with squared or other irregular shaped portions 6 to receive any suitable wrench or tool to adjust them. Each bolt is provided with a shoulder e and with a reduced outer end passing through openings in the plate C so that the latter seat upon the shoulders, and the reduced outer ends are screw threaded as at e to receive the set nuts 6 which bear upon the plate C and clamp it against the shoulders e.

The adjustment is preferably effected by removing the parts from the casing, though this is not regarded as essential; after loosening the set nuts 0 the bolts E are turned by a wrench or other suitable means to bring their shoulders at a suitable distance below or away from the plate C and the nuts are run down on the threads 0 to force or seat the plate against the shoulders of the bolts, thus forcing the strings against the sounding board bridges to increase the pressure of the strings on the bridge. Obviously when the pressure is to be lessened or decreased, as when the sounding board has buckled up from dampness or other cause, the bolts are reversely turned a suitable distance after the nuts are loosened and the latter are then again run down to position. The plate and strings may be adjusted to increase or decrease the bearing or pressure of the strings on the bridge as may be desired as the plate may be moved in either direction to raise or lower the strings from or toward the bridge, and then may be locked in position. It is apparent from this disclosure that the string plate C is regulated below the pin-block to move and adjust the plate and strings toward and away from the bridge to create increased or decreased bearing of the strings against the bridge. It is obvious that the means for accomplishing the adjustment may be varied Without departing from the scope of my invention.

The present disclosure represents a prac tical embodiment of my invention, but I desire it to be understood that the apparatus shown is merely illustrative and that the invention may be exemplified in other Ways.

I claim 1. An upright piano having a back-frame, a sounding-board bridge, a string-plate secured at one end to the frame, and means to adjustably space the other end of the plate to and from the frame to vary the pressure of the strings on the bridge.

2. A piano having a back-frame, a sounding-board bridge, a plate carrying the strings and secured at one end to the frame, screw bolts adjustable in the back-frame and having shouldered and threaded outer ends to support the free end of the plate, and nuts engaging the threads to force the plate against the shoulders of the bolts to force the strings on the bridge.

3. A piano having a back-frame, a sounding-boarl bridge, a pin-block, a plate carrying the strings, means to secure the top of the plate to the frame, a series of adjustable securing devices entering the frame at the bottom of the plate and having adjustable seats for the lower end of the plate, and means to secure the plate on said seats to force the strings on the bridge.

In testimony whereof I aflix my signature in presence of tWo Witnesses.

FRANK J. V. VVEISER.

Witnesses:

J. MoRoBER'rs, H. O. LUST.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

